There are a number of connectors available in the market which have terminals which cooperate with conductive areas on a printed circuit board. In order for the electrical connection to be established and maintained between the terminals and the conductive areas, the electrical connector must be secured to the printed circuit board.
In the past, one method of attaching the connector to the board was to use screws. The screws would cooperate with openings on the connector and the printed circuit board to maintain the connector in position. Although this provides a positive securing means, the use of screws was labor intensive, required the use of valuable board real estate, and was expensive as many separate pieces were required.
Other methods include using metal clips or other separate board lock devices to secure the connector to the board. These metal clips and separate board lock devices have the same disadvantages as described above.
In an effort to minimize the board real estate occupied by the various board lock features described above, and in order to minimize the cost associated therewith, various connectors have employed the use of integral plastic posts which extend from a bottom surface of the connector. The integral posts are dimensioned to extend beyond the printed circuit board and are generally used as a temporary hold down until the connectors are heat staked or soldered in permanent position. However, although these integral posts maintain the connector in position relative to the board, in many instances the connector is not firmly held in position (i.e. the connector has some freedom of movement relative to the board). This is due to the fact that dimensions cannot be precisely controlled during the molding of the posts and the manufacture of the printed circuit boards. Consequently, in many instances the dimensions are such to allow the board to float relative to the connector. This is an unacceptable result, particularly in application in which close centerline spacing of the contact areas is required.
Other integral posts have been dimensioned to ensure for a tight frictional engagement between the side walls of the opening of the board and the side walls of the posts. This configuration results in erratic insertion forces because of the tolerances associated with the opening and the post. Consequently, this type of interference fit can lead to unacceptably high insertion forces or unacceptably low retention forces.